1. Field of the Invention
The present invention relates to a waveform display device capable of acquiring various data (a position, a speed, a torque, and the like) related to a driving axis by being connected to a numerical controller of a machine tool, and displaying the data as waveforms.
2. Description of the Related Art
Manufacturing costs, quality of a finished product, and a life of a production facility are significantly important to a user of a machine tool. For this reason, the user of the machine tool performs an operation below in some cases. First, a current processing program or various parameters are changed to shorten a cycle time, improve quality of a processed surface, and reduce an impact on the machine tool due to acceleration and deceleration of a axis. Then, whether a desired state is achieved is determined by comparing waveforms of data obtained before and after the change. When the desired state has not been achieved, the processing program and the parameters are changed again. The desired state is nearly achieved by repeating this operation.
Here, the cycle time of the processing program affects cost of the finished product, quality of the processed surface affects quality of the finished product processed by the machine tool, and the impact on the machine tool affects a life of the machine tool. In particular, with regard to mass-produced finished products, a small difference may generate a great difference in manufacturing cost or damage to the production facility. Thus, adjustment of the processing program and the various parameters is an operation that needs to be sufficiently examined.
A waveform display device is used in this important operation. When data obtained after adjustment is compared with data obtained before adjustment, a clue to evaluation or improvement of a state after adjustment can be obtained. JP 5302371 B1 discloses a numerical controller having a function of displaying physical data of the machine tool. In addition, JP 5416238 B1 discloses a waveform display device having a function of managing data.
In general, to acquire necessary data, first, a type of the data to be acquired (a position, a speed, a torque, and the like) is selected, and a data acquisition condition such as a sampling period of the data and a data acquisition start/end trigger is set. Thereafter, a processing program is executed to acquire desired data.
Here, a case is considered in which data is acquired by a processing program A below having five processes to display a waveform (see FIG. 12).
Process 1: Milling 1
Process 2: Drilling
Process 3: Rigid tap (screw cutting) processing
Process 4: End milling
Process 5: Milling 2
In this case, conditions necessary for the respective processes are as below.
In Process 1, necessary data is speeds in an X-axis and a Y-axis and a spindle torque, a sampling period is 10 msec, a data acquisition start trigger is N number 100, and a data acquisition end trigger is N number 200.
In Process 2, necessary data is a speed in a z-axis and the spindle torque, a sampling period is 5 msec, a data acquisition start trigger is N number 300, and a data acquisition end trigger is N number 400.
In Process 3, necessary data is a position on the z-axis, the spindle torque, and a spindle position, a sampling period is 1 msec, a data acquisition start trigger is N number 500, and a data acquisition end trigger is N number 600.
In Process 4, necessary data is a speed in a B-axis (additional axis) and a jerk, a sampling period is 2 msec, a data acquisition start trigger is N number 700, and a data acquisition end trigger is N number 800.
In Process 5, necessary data is the speeds in the X-axis and the Y-axis and the spindle torque, a sampling period is 10 msec, a data acquisition start trigger is N number 900, and a data acquisition end trigger is N number 1000.
N number refers to a sequence number described in the processing program (see FIG. 12).
In this case, two data acquisition methods below are considered in a present state.
<Data Acquisition Method 1>
A first method sets all necessary data types as an object to be acquired, and acquires data using setting of a shortest sampling period. In the above example, types of acquired data need to be set to the speeds in the X-axis and the Y-axis, the position and the speed in the Z-axis, the speed and the jerk in the B-axis, the spindle torque, and the spindle position, a sampling period needs to be set to 1 msec, a data acquisition start trigger needs to be set to N number 100, and a data acquisition end trigger needs to be set to N number 1000.
<Data Acquisition Method 2>
A second method prepares the five types of data acquisition conditions, and temporarily suspends the processing program at the time of starting the respective processes. Then, the second method changes a data acquisition condition to a data acquisition condition corresponding to each of the processes and starts to acquire data. Thereafter, the second method resumes the processing program.
Data acquisition method 1 has demerits in that a lot of unnecessary information is present, a size of acquired data is large, and it takes time to extract data of a part desired to be compared. Specifically, in Process 1, even though data of the B-axis and the like is unnecessary, the data is acquired.
In addition, a sampling period of 10 msec is sufficient. However, if a sampling period is set to 1 msec, the amount of data will increase more than necessary. Further, in Process 2, data of only the position on the Z-axis and the spindle torque is evaluated in drilling. In this case, only data in Process 2 needs to be extracted from all data, and then unnecessary data such as the X, Y, and B-axes needs to be removed since the unnecessary data hinders accurate and rapid evaluation of data.
Data acquisition method 2 is considered to avoid the demerits of Data acquisition method 1. However, an operation time for data acquisition increases since the processing program is temporarily suspended and a data acquisition condition is changed.
JP 5302371 B1 and JP 5416238 B1 fail to disclose a device capable of acquiring data by setting a plurality of data acquisition conditions when data is acquired once.